Fuel-burning panel heater



April 1952 w. 5. CARTTER FUEL-BURNING PANEL HEATER 3 Sheets-Sheet 2Filed Aug. 7, 1948 INVENTOR. WILLIAM G. CARTTER A 7' TORNEKS.

April 29, 1952 w T R 2,594,608

FUEL-BURNING PANEL HEATER Filed Aug. 7, 1948 s Sheets-Sheet :5

INVENTOR: WILLIAM G. CARTTER A TTORNEYSZ Patented Apr. 29, 1952 UNITEDSTATES PATENT OFFICE 7 2,594,608 FUEL-BURNING PANEL HEATER William G.Cartter, Monrovia, Calif., assignor, by

mesne assignments, to Affiliated Gas Equipment, Inc., Cleveland, Ohio, acorporation of Delaware Application August 7, 1948, Serial No. 43,038

14; Claims.

The application refers to space heatersof a type which rely chiefly uponthe effect of. radiated heat to provide the necessary heating effect.The particular heaterhere involved isonecommonly designated as anoverhead heater and-because of its construction. is more generallyadapted to use for heatinglarge spaces like .factories, waiting roomsand otherlarge. quarters where floor space is at a premium, .where.alarge volume of heat is required and. where there is ample spaceoverhead in which. to locate the necessary heating equipment.

Considerable attention has devoted during recent years to theprovision-of space heater commonly designated as unit heaters, theunitsiof which are adapted to be spotted in. advantageous locationsoverhead within. the space which. is to be heated. In making use ofspace heaters. for heating quarters of very large Volume, avariety ofmeans has been resorted to. for the distribution of heat. The usual typeof heater employed for such purposes has not depended so much uponradiation as upon convection and has more frequently resorted to forcedair circulation. by use of fans. Although forced air heating, units arecapable of disseminating a substantial amount of heat into spaces oflarge volume because of the fact that there is a strongv draft inducednecessary to circulate the air, they are more often than not a source ofconsiderable discomfort to persons within the space. Person's locatedtoo near the source of heating find that the air in that quarter isoverheated. Persons remote from the source of heat, though not'suf-'fering an overheated effect, nevertheless are troubled by the ratherstrong circulation of. air about them even though the air is warmed to acomfortable temperature.

Those space heaters depending in part at least upon radiant heat havebeen constructed in such a way that there is a very limited dissipationof radiant heat and because of the'compact construction of overheadheaters previously utilized, the effect of radiant heat is carried toonly-'a limited area around the heating unit. Often when a sufficientnumber of those units were provided to heat all of a floor area by theuse of radiant heat, the cost of equipment. and the space required forthe installation may not be warranted by the results experienced,

It is therefore among the objectsof. the invention. to provide a newandimproved overhead heater which is so constructed that it' provides"substantially a maximum amount of heating surface at the source of heatthereby raising the efficiency of the unit to a very high degree.

Another object of the invention is to provide an overhead radiant typeheater having radiating surfaces which extend substantially through,-out theentire area of thexsourccof. heat, thereby utilizing virtuallyall of the space Within the heater as a source of radiating heat energy.

Still another object of the invention isto provide a new and improvedoverhead radiant type unit heater which is so constructed that it iscapable of directing virtually all of the radiant heat generated in theheater most advantageously over an area to be heated. and whereinsubstantially a maximum share of heat generated by the heater isdirected by radiation rather thanconvectioninto the space to be heated.

A further object of the invention is to provide in a radiant type heatera new and improved heating element or heating source which has the formof plates back to back, the entire areas of which provide means fromwhich radiant heat may be 7 emanated in an extremely eiiicient manner.

Still further among the objectsof the invention is to provide a new andimproved unit type overhead radiant heater which is relatively low inmanufacturing cost in proportion to the square foot area oiheatingsurfaces, which makes multiple use of certain elements of the devicethereby greatly minimizing the quantity of materials used in the heaterand the cost of assembling the same without imparing the ovarall heatingefiiciency.

Included also among the objects of the invention is the provision of aunit type radiant heater so constructed that the quantity of heat may becontrolled with relative ease, which can be built inexpensively inmultiple units so as to be accommodated to spaces varying greatly insize, and which because of its new and improved construction is capableof spreading a very Wide pattern of radiant heat uniformly in everydirection from the heating source.

With these and other objects in view, the invention consists in theconstruction, arrangement and conbination of the various parts of thedevice whereby the objects contemplated are attained, as hereinafter setforth, pointed out in the appended claims and illustrated in the ac-,companying drawings.

In the drawings:

Figure 1 is a side elevational view partly broken away showin one unitof the radiant heater.

Figure 2 is a plan view partially in section showing one of thecomplementary sides of the radiant heater taken on the line 2-2 ofFigure 1 and. drawn to a-larger scale.

Figure 3 is a fragmentary vertical sectional view taken. on the line 3-3of Figure 4.

Figure 4 is a vertical sectional view of one of complementary of theheater.

Figure .5 is a vertical sectional view of one side of the-heater takenat right angles to the view shown in Figure 4 and ontheline -55 ofFigure 4.

Figure 6 is a fragmentary vertical sectional view showing the vaneconstruction and mounting.

Figure '7 is a fragmentary vertical sectional view taken on the line '|lof Figure 4.

Figure 8 is a vertical sectional view taken on the line 8-8 of Figure 4.

Figure 9 is a vertical fragmentary sectional view of another type ofvane structure.

In the embodiment chosen to illustrate the invention there has beenselected an overhead unit type heater constructed in a manner whichpermits it to be readily suspended at virtually any heightfrom a ceilingso that it can be adjusted to proper relationship with the floor of thespace which is to be heated. It will also become apparent as thedescription proceeds that almost any number of units of the typeillustrated can be located, end to end or otherwise, thereby to servicea very substantial area where the space to be heated is large. In order,however, to simplify the description, a single unit is here illustratedin detail.

In the unit selected there is no framework as such but instead thevarious elements cooperating together stiffen the assembly sufficientlyto dispense with a separate frame. There are straps, however, attachedto the unit which serve to support the unit upon beams of the ceiling orother portions of the building structure. Because excessive weight hasbeen avoided in the unit, straps II need not be of especially heavyconstruction. Additional support may be provided by vertical strips I2which extend along opposite sides of the unit.

An important part of the unit is embodied in the plate panels whichprovide a source of radiant heat. In the selected embodiment four panelsI3, I4, I and I6 are utilized, all of the panels being visible in Figure2. These panels are of special construction and are matched so that, forexample, panels I3 and I5 are adapted to fit together back to back andare provided with stiffening flanges I1 and I8 extending around thesides and the top, thereby closing the edges of the panels I3 and IE onall sides except the bottom. The panels l4 and I6 are similarlyconstructed. Because of the fact that each side of the unit hereillustrated is substantially identical, a detailed description will begiven for only one side.

Each of the panels I3 and [5 as illustrated in considerable detail inFigures 2, 4 and 5 has its central portion stamped out in a veryparticular pattern. The stamping process provides in the panel I3 aseries of Walls 20, 2G, 28 forming portions of heater channels or tubes2 I, 2 I, 2|". As here illustrated the walls 20 form a. series ofoutwardly extending triangular channels having outer ridges Z2, 22, 22"and having inner ridges 23, 23', 23". Along the ridges 22, 22, 22" ofthe heater channels 2|, 2|, 2| respectively, except the channels at theoutermost edges, there are provided depressions or recesses 25 whichextend inwardly a distance approximately meeting a baffle plate 5retained by a single screw 6 at the center of each channel. The recessesare alternated in adjacent heater channels of the plate panel I3, forexample, so that they present a staggered pattern, thereby appearinguniformly over the entire central portion of the plate panel.

As most readily seen in Figure 2 the angles formed between the outsidesurface of vertical walls of adjoining heater channels are not less than90. For example, the angle at the ridge 23 formed by adjoining wall 20of the channel El and adjoining wall 25' of the channel 2| will be foundto be something greater than By giving the panel this shape, heatradiated from the surface of the walls will at no time be reflected fromany of the other walls before passing out into space. In other words,secondary reflection of radiant heat is avoided.

In the vertical channels I and I adjacent the outer limits of theheater, bafiies 8 and 8 are employed to obtain a tortuous path in placeof depressions heretofore described in connection with the othervertical channels. The bafiie plates 8 and 8 are disposed verticallybetween the plate panels I3 and I5 and are formed with outwardly turnedears 9 and 9', said ears being turned outwardly in opposite directionsin staggered relation.

The plate panel I5 is constructed similar to plate panel I3 as will beapparent from an examination of Figures 2 and 5 with the exception thatthe recesses 25a, are staggered with relation to the recesses 25 of thewalls 20, 20, 20" of the plate panel I3. The staggered relationship ismore readily apparent in Figure 5. By thus arranging the recesses ineach of the heater channels there is provided a tortuous passage for theproducts of combustion as they pass upwardly within the space betweenthe oppositely positioned plate panels I3 and I5. It will further beapparent that the entire space between the plate panels I3 and I5 isoccupied by the series of parallel adjacent and vertically positionedheater channels 2| formed between corresponding wall portions 20, 20,20" of the oppositely disposed plate panels. Along the edges 23 therespective heater channels are closed and at the outer edges theoutermost heater channels are closed by a junction of the flanges I1 andI8.

Near the bottom of the respective walls 20, 20, 20" forming the heaterchannels are outwardly extending triangular segments 26 by whichconstruction the lower portions of the plate panels identified by thereference characters 21 and 28 form an enlarged common combustionchamber 29. The combustion chamber 29 communicates uniformly with all ofthe heater channels 2 I, 2|, 2|. Similarly triangular segments 30 at thetops of the walls 20, 20, 20" extend outwardly to portions 3| and 32 ofthe respective plate panels, thereby forming a common flue chamber 33which is in communication with the tops of all of the heater channels2|, 2|, 2|". The flue chamber 33 communicates through an opening 34 witha vent manifold 35 from the central hood through which the flue gasesare conducted to an outlet vent 36. Extensions 35 of the vent manifoldare located on opposite sides, the extension 35' on the right being aduplicate of the extension 35 on the left. To improve the ventingoperation a baflle 31 may be provided extending from a locationintermediate channels 2|" and 2I', as best seen in Figures 3 and 4,upwardly through the opening 34. Flow is improved by curving the top ofthe baffle toward the vent 36.

To eliminate baokdraft or downdraft through the panels the central hoodof the vent manifold "35 is made substantially wider than the width ofthe combined plate panels. The proportion of the width of the ventmanifold or hood to the width of the plate panels is best illustrated inFigures 3 and '7.

To insure the effectiveness of both the venting process and theelimination of downdrafts, a structure of special design may be includedbejacent'the entrance-to the vent-36.

Beneath the vent there is provided an inverted V-shapedstructure havingopposite sides38 and 38' which join along a line 39 atthetop. The shapeof'the structure can best be seen in Figure 7*Whereas the length of thestructure. is more readily discernible in Figure 4. At each end ofthe-structure there are provided draft deflectors for directing fluegases entering the manifold 35 in a pathtoward the vent 36. One of thesedraft deflectors, namely, the deflector for the left panel isillustrated in Figures 2 and 4. The draft deflector consists of a fiatsloping plate 61 provided with wings 68,the upper edges of which areturned outwardly to form flat horizontal portions 68. At the outer edgesof the sections 68' are walls 69 having end edges 69' directed inwardly,as shown in Figure 2.

By this arrangement, if there should be a suddendowndraft or backdraftthrough the vent 36, it will be deflected into the atmosphere at a'point adjacentthejunction of one set of plate panels withthe other whichis a location removed from the-opening34 by a distance roughly equal toone-half of the overall width of the plate panels.

Consequently there is no tendency for a backdraft or downdraft to travelthrough the vent manifold 35 andopening-34 into the heater channelsand'from there pass downwardly to the combustionchamber to apositionwhere it would be apt'tosnuff-out the pilot light.

One of the purposes of the structure just described is'todijvorceconditions-in the vent pipe from operation of theburners and the heatingportion oftheappliance. This isfor the purpose of maintaining-normalcombustion and fluegas escape,release of vent conditions such asa'strong updraft,' a, blocked vent pipe or a'strong backdraft. The pathdefined by the structure just described for flue gases Will be found onetending to confine the flowof fluegases to the center portion'of thevent manifold and to direct those gases directly; to the bottom entranceof the vent 36. By making the vent manifold relatively wide around thatportion of the manifold immediately adjacent the vent pipe, draftconditions may be maintainedin a .manner notmaterially affecting burner,conditions.

The gas burning features. and appropriate mechanism are located largelybeneaththe plate panels. The gas, burning mechanism. is fed throughthesupply. pipe, 411 located. at the .left of ltheunit asnviewed in Figure1, The supply pipe is retained against the frame by brackets 4| and-Handis curved so thata lower portiony43 of ,thesupply pipe lies, in'ahorizontal position at the bottom, of the unit. A plate It prevents someof the heat fromthe bafiies, reaching and overheatingthe supply, pipe40. The supply pipe leads to a gas pressure regulator 44 and gas fromthepressure regulator passeslto a shut-off valve 45 and fromtherethrough an elbow 46 to a.T 41 shown .in Figure 8. From-theT a pipe 48conducts, the gas to burnersin the, portionof the uniton the left sideas viewed in Figure lgwhich is the portion made, the subjectmatterofthis description The pipe 48 is led into an L 49' and a nipple50 conducts gas through a T 5| from which. Venturi tubes 52 and.,53,supply left? and right'hand burners 54 and 55, respectively. As clearlyshown in Figures 4v and 5 the burners are relatively narrow and also,long so that twoiof them extend throughout the. entire breadth .of theplate panels. Asomewhat V-shaped guard 62 6 beneath the'burners iserves,as v a fiash-outbaflie when the burners are being lit:

For operating th'e. gas burning equipment there is provided. a handle56..for turning. the. shut-off valve 45 off and on.. Apilottline51isfedfrom the inlet side of the shut -lofi valve and supplies a-pilot.burner '58 which is located adjacentthe burner 55 and also adjacent-aburner .59 which is :one ofthose usedon the right-hand side of the unitas viewed in Figures 1 and 4'. With the pilot burner locatedinthe centerofthe heater and the main; burners extending: a relativelygreat'distance upwardly onleach side in the: embodiment hereindescribed,there is a momentaryv delay in fullburner ignitionzdue to thetimerequiredfor flame 1 propagation. The time delay: means that aquantity of unburned gas escapes into the spaces around the burnersbefore ignition. When ignitedthe gas expands rapidly and would flash outdangerously except for the interposition of the fl'ash-out: bafile 62.

As previously indicated, the-lowerportions of the plates i3 and I5 formthe combustion-chamber Hand it should benoted thata vestibule forms ajunction between the combustion chambers on the opposite sides of: theunit, the pilot burner being located within the vestibule. A separatecasing BI is formed about the gas burning mechanism and houses apre-combustion chamber 64 beneath but :communicating with the combustionchamber 29. Air isadmitted into the pre-combustion chamber throughopenings: 63. The casing is made removable'byproviding a hinge 65"at theleft end of the left panel as viewed in Figure 4 and a snap fastener 66'atthe righthand endofthat panel. The right panel issimilarly equipped.

By reason of the pattern of the faces of the plates [3,14, I5 and 15; avery elT'ective overall source of heat radiation is provided. Because ofthe angular relationship of'the walls forming the heater channels andthe presence of the recesses with facespitched so-that they faceinvarious directions, there is an. especially well-defined spread ofradiated heatin alldirectionsfrom the unit and also to some extent in adownward direction.

Tobe effective, however, the radiated heat or at least the largerportion of 'it'must bedirected toward the floor area of the space to beheated inasmuch as this is the' portionof theroom occupiedby workers or:other persons using the space which benefits most by the radiantheat. To-accomplish this there is provided aseriesof baflles, vanes or louversdisposed in-thepath of radiated heat emanating from the unit. The vanesselected for this purposeare preferably as thin as can bemadecommensurate with suitable strength so that they-will interfere '-aslittle as possible with the distribution of the radiated heat. Thepurpose of "the vanes, which dictates: the character'ofthe structureselected, is to reflect or deflect the heatradiatingfrom the unitdownwardly over the desired areaof floor space In this connection itshouldbe noted that-it is-desirable'to deflect a substantial quantity orheat atan angle between 30 and 40- from horizontal which is an areaordinarily difficult to reach in use of "overhead'heaters; In thismanner substantially all of the radiant heat will be utilized tobestadvantage.

In one of the. embodiments selected for the purpose ofillustrationdefleotors orvanes in. are arranged in parallel relationshipand disposedhorizontally. Eight vanes are shown on eachside' of thedevice but the precise number is not material so long as there are asuflicient number of vanes having breadth great enough to catch radiantheat which may start in an upward direction from the respective plateand preventing little, if any, radiant heat having an upward path frompassing undisturbed toward the ceiling of the space. It will beappreciated that the number of vanes will bear a relation to the breadthin order to trap all of the radiant heat and defiect and spread it tothe extent desired. At the same time it will become clear that forpractical reasons as well the breadth of the vanes cannot be excessivelygreat while at the same time providing a compact and efficient heaterunit.

In one modification shown, the vanes are curved slightly and directedoutwardly and downwardly. This is for the purpose of spreading virtuallyall of the radiant heat toward the floor well outwardly from the unit.The amount of tilt or I downward pitch of the vanes may also be varied,depending upon the height of the unit above the floor and the floor areawhich is needed to be heated. The latter element may vary to some extentdepending upon outside temperatures or, on the other hand, dependingupon the desired inside temperature. The vanes may, for more eflicientoperation, be of etched aluminum on the lower sides and painted black onthe upper sides.

For securing the vanes in place there are provided inside strips "Hhaving lugs 12 extending outwardly therefrom for engagement with thevanes '10. The lugs 12 are uniformly spaced apart distances determinedby the desired spacing of the vanes 10.

The vertical strips l2 previously referred to are anchored at their topends by means of bolts 13 to brackets 14 and the brackets in turn aresecured by bolts 15 to the straps II. The brackets, incidentally, areattached to the tops of the plate panels. At the bottom ends the strips[2 are attached by screws 16 to the lower edges of the plate panels atwhich point the casing 6| is also attached. By this arrangement thestrips l'2 may be said to form part of the frame.

Bent inwardly from the strips I2 is a series of lugs 1'! which arespaced the same distance apart as the lugs 12. In the presentembodiment, however the lugs 11 are off-set downwardly to a slightextent from the position of lugs 12. As

shown, the vanes are supported by the lugs 12 along one edge and thelugs 11 along the opposite edge to which they may be secured by suitablescrews 18, details of which are best illustrated in Figure 6.

A better idea of the character of the vanes or louvers can be gainedfrom an inspection of Figure 2. As is shown it will be apparent that thevanes 10 include a portion 19 which extends around the end edges of theunits. The topmost vane in each instance may be out off at an end 80 soas not to interfere with the outward spread of the vent manifold 35. Theremaining vanes, however, may extend clear across the face of each sideof the unit heater.

The selection and shape of the heat deflecting vanes depends to a largeextent upon how it is desired to disperse radiant heat over the floorarea. Improved dispersion over a larger area may be accomplished byvanes of the character illustrated in Figure 9. As there shown vanes 10are curved outwardly with the convex side downwardly. These vanes'may beattached to strips [2 and H by the same means as previously described.In this case, however, lugs 12 may be tilted downwardly to a slightextent and lugs 1'! extended horizontally inwardly for the betteraccommodation of the vanes. Vanes of the type of vanes 10 may be morenumerous and located closer together if desired.

In use the unit heater is adapted as previously mentioned to besuspended near the ceiling level of a space to be heated. One or more ofthe units may be used as occasion may require. The size of the unit willbe selected in conformance with the volume of the space to be heated andthe floor area as well as the particular shape of the floor area. Alsotaken into consideration is the ceiling height and the distance of theheater unit above the floor. These circumstances will dictate to someextent the number of heaters used and also the size of the unitsutilized as well as the pitch of the deflector vanes.

In operation gas is piped to the valve 45 and pilot burner 58 which islit and remains lit. Whenever the burners are to be lighted it isnecessary only to turn the valve handle 56 to open position for theshut-off valve 55. In this position gas will flow to the burners 54, 55.59, etc. As soon as gas reaches the ends of the burners 55 and 59,respectively, adjacent the pilot burner 58, the gas will be ignited andthe flame will trail across all of the burners until all jets iii theburners are ignited. The flame at the burners may be turned up or downat will. As the burners continue to burn they draw fresh air through theapertures 63 and the hot products of combustion pass upwardly throughthe several heater channels within which a tortuous path is followed.During passage the greater part of the heat of the products ofcombustion is absorbed by the walls of the plate panels so that theproducts of combustion greatly reduced in temperature pass around thebaffles 3'! and thence through the vent passage 34, the vent manifoldand upwardly through the vent 36. The plates at this point becomeextremely hot throughout practically their entire surfaces and become asource of radiant heat of considerable area. Because of the large areaof the plate panels there is a markedly less tendency for overheating atany particular place and at the same time there is emanated from theplates a very large volume of radiant heat. Radiant heat is in turnreflected outwardly and downwardly by the vanes HI or the vanes Ill.Some convection may also assist in the distribution of the heat as airrises in the vicinity of the heater units and after being heatedcontinues to rise toward the ceiling. The great percentage of heat,however, is dissipated as radiant heat. The detrimental effect ofdowndrafts or backdrafts is minimized or, in fact, eliminated aspreviously noted. When the space has been sufficiently heated it isnecessary only to turn off the shut-off valve at which point all of theburners are turned off and only the pilot continues to burn.

By providing combustion chambers interconnected by the vestibule 69 areasonably uniform temperature is maintained in the combustion chambersadjacent the burners. The interconnection of the vent passages islikewise helpful in maintaining a uniformity of heat delivery throughoutthe entire area of the unit. In functioning as described, the heaterunit provides highly desirable radiant heat sufficient to heat a givenarea entirely in the absence of undesirable and objectionable drafts.

While I have herein shown and described my invention in what I haveconceived to be the most practicaland preferred embodiment, it isrecognized ithat departures may belmade therefrom 'iwithinlthe. scope ofmy invention, whic'li is not to be limited-to :the details A disclosedherein but'is'torbe accorded the full iscope oflthe claims so astouembrace any and all equivalent tdevices. Having described myinvention, whatiliclaim asnew and d'esire to secure by Letters Patent-isi 1. A: .radiant-itype'gas burning heater adapted for installation inthe upperlimits of a room comprising in combination -fu'el combustionmeans means for collectingthe products of combustionproduced by'saidfuel combustionmeans disposedsuperadjacent 'said combustionmeansand having anopening in the top thereona hollow-heat exchange unit;having a lower open lend communicating with said fu'el-combus'tion meansand an upper flue outlet -communicating with saidcollecting-means, and=comprising means-defining a pluralityref-verticallydisposed tortuousgas passages adapted toduct said products -of combustion upwardly a'ndto radiate heat produced-*thereby; "and-means for -reflecting heatradiated by said-heat exchange unitdownwardly towards the-:floorofsaidroom, said means comprisinga plurality -of vertically spacedlong'itudinally' horizontal reflector vanes circumscribing in spacedrel'ation said -heat exchange -unit; the

' lower surfaces pf saidva'nes being finished soas to bepredominantlyreflective, the upper surfaces of said-vanesbeing-darkened-so-as-to-be predominantly "absorptive.

2. A-radiant-type heater having -fuel combustion means a-hollow* heatexchange unit having an open lowerend andanupper flue outlet, said unitbeing dispos'ed superadjacent and communicating -with 4 saidcombustion-means,

thereby being adapted to duct products of combustion upwardly andtoradiate-heat generated by said fuel combustionmeans into thespacesurroun'dingsaid heatensaid' heat exchange unit comprising apair' ofsheet metalpanels disposed vertically in "back=to=backrelation -havingopposite edges joinedtogether,"each-of said panels being formed witlr'a'plurality of inwardly directed "grooves defining iparallel vertically---disposed gas passagesand havinga ridge -between each of said respective"grooves, each of said ridges"being-formedwith "a'plurality 'of inwardlydepressedsections staggered relation with the corresponding'inwardlydepressedsections of the opposite panel; each of said groovesbeingformed by sidewalls'havinga surface configuration such that a'1ine"normal1 to"thesurface' at "any point extends outwardly'into said"space uninter 3. A 'ra'diant type heater having fuel combustion means"and "a "hollow' 'heat'exchange unit having a lower openend and anupperflue 'outlet, "said 'unit"bein"g "disposed 'supe'radjacent' andcommunicating "with said combustion f means, thereby being adapt'edtUduct"pro'ductsof 'combustier! upwardly "and to (radiate heat-gei'ierat'ed by said fuelfcombustionmeans intotlie space surroundingsaid heater, said-heat exchange unit comprising a pair of sheetimet'alipanels disposed vertically in backto-ba'ck relation -iha'vingopposite edges-joined together, each of said panels being. formed with aplurality of inwardly depressed .V shaped-grooves defining parallelvertically disposed gas passages and having aridge between each-:ofsaidrespective grooves each of v said ridges being'formed with ai--plurality of inwardly depressed sectionsspaced in staggered relationwith the-corresponding inwardly de--- pressed sections of the oppositepanel, each of said grooves-having side walls disposed at greater thanwith'respect to each other.

itAradiant-type heater having'fuel combustion-means, a hollow heatexchange'unit having a lower'open end and an upper flue outlet, saidunit being "disposed superadjacent and communicating. with saidcombustion means, thereby being adapted 'to duct products of combustionupwardly and to radiate heat generated by said fuelcombustion meansintothe space surrounding said heater, said heat exchange'unitcomprising, a pair'of sheet metal panels disposed vertically inback-to-back relation having oppositeedges joined together, each-ofsaid'panels being formed with 'a plurality of inwardly depressedV-shaped grooves defining parallel vertically-disposed gas passages andhaving a ridge between each of said respective grooves each of said*ridgesbeing formed with a plurality of inwardly depressed sectionsspaced in staggered relation with the corresponding inwardlydepressedsectionsof the opposite panel,=each of said grooves having sidewalls disposed at greater than 90 with respect to each other, and meansfor reflecting the radiant heat downwardly, said means comprising aplurality of spaced parallel horizontally disposed reflector vanescircumscribing-saidheat exchange unit inspaced relation therefromadapted to reflect downwardly heat radiated by said heat exchangeunit.

5;- A-radiant-type heater having fuel combustion "means anda 'hollowheat exchange unit having an'open lower end and an upper flue outlet,said unit being disposed superadjacent and communicating with saidcombustion means, thereby being adapted to duct products of com bustionupwardly and to-radiate heat generated by saidfuel combustion means intothe space surrounding said heater, said heat exchange unit comprisingapair of panels disposed vertically'in spaced-relationhaving-oppositeedges joined together, each of said panels being formed with apluralityof inwardly directed grooves defining parallel verticallydisposed gas passages and having a ridge between each of said respectivegrooves, eachof said ridgesbeing formed with a plurality ,ofinwardlydepressed sections in staggeredrelation with the corresponding inwardlydepressed-sections of the opposite panel.

6; Aradiant-type heater-having fuel combustion means; a hollow heatexchange unit having an-open lower end and an upper flue outlet, saidunit being disposedsuperadjacent and communicating'w-ith said combustionmeans, thereby beingadaptedtoduct products of combustion upwardly'and toradiate heat generated by said fuel combustion means into the spacesurrounding said :heater, said heat exchange unit comprising a pa'irofpanels disposed vertically in spaced relation having opposite edgesjoined'together, each of-saidpanels being formed with a plurality ofinwardly directed grooves defining parallel vertically'di'sposed gapassages-and having a ridge between each of said respective grooves,eachof said'ridgesbeing formed with a plurality of inwardly? depressedsections in staggered relation with the-corresponding inwardly'depressedsections of the opposite panel, and means 'for reflecting the radiantheat downwardly, 'said means comprising a plurality of spaced'parallelhorizontally disposed reflector vanes circumscribing "said heat exchangeunit in spaced relation therefrom.

7. A radiant-type heater comprising fuelcombustion means, collectormeans positioned superadjacent said combustion means for collectingproducts of combustion, said collector means being open at the topthereof, a hollow heat exchange unit having a lower open endcommunicating with said combustion means and an upper flue outlet incommunication with and di p subjacent said collector means adapted toduct the products of combustion upwardly and to radiate heat generatedby said fuel combustion means into the space surrounding said heater,said heat exchange unit comprising a pair of sheet metal panelspositioned back-to-back and having a vertical partition therebetween,each of said panels being formed corrugated, thereby defining incooperation with said partition parallel vertical gas passages, each ofthe corrugations havin a ridge formed with inwardly depressed segmentsextending into said gas passage and being in staggered relation with thecorresponding inwardly depressed segments of the oppositely disposedpanel, thereby causing said products of combustion to follow a sinuouspath upwardly, each of said gas passages being open at the top thereof.

8. A radiant-type heater comprising fuel combustion means, collectormeans positioned superadjacent said combustion means for collectingproducts of combustion, said collector means being open at the topthereof, a hollow heat exchange unit having an open lower endcommunicating with said combustion means and an upper flue outlet incommunication with and disposed subjacent said collector means adaptedto duct the products of combustion upwardly and to radiate heatgenerated by said fuel combustion means into the space surrounding saidheater, said heat exchange unit comprising a pair of sheet metal panelspositioned back-to-back and having a vertical partition therebetween,each of said panels being formed corrugated, thereby defining incooperation with said partition parallel vetrical gas passages, each ofthe corrugations having a ridge formed with inwardly depressed segmentsextending into said gas passage and being in staggered relation with thecorresponding inwardly depressed segments of the oppositely disposedpanel, thereby causing said products of combustion to follow a sinuouspath upwardly, the outer surface of each of said corrugations being soformed that a line normal to the surface thereof passes into the spacesurrounding said heater without interruption, each of said gas passagesbeing open at the top thereof.

9. A radiant-type heater comprising fuel combustion means, collectormeans positioned superadjacent said combustion means for collectingproducts of combustion, said collector means being open at the topthereof, a hollow heat exchange unit having a lower open endcommunicating with said combustion means and an upper flue outlet incommunication with and disposed subjacent said collector means adaptedto duct the products of combustion upwardly and to radiate heatgenerated by said fuel combustion means into the space surrounding saidheater, said heat exchange unit comprising a pair of sheet metal panelspositioned back-to-back and having a vertical fiat partitionthere-between, each of said panels being formed with substantiallyV-shaped corrugations, thereby defining in cooperation with saidpartition parallel vertical gas passages, each of said corrugationshaving a ridge formed with inwardly depressed segments extending intosaid gas passage and being in staggered relation with the correspondinginwardly depressed segments of the oppositely disposed panel, therebycausing said products of combustion to follow a sinuous path upwardly,the angle between adjacent walls of said V-shaped corrugations beinggreater than each of said gas passages being open at the top thereof.

10. A radiant-type heater comprising fuel combustion means, collectormeans positioned superadjacent said combustion means for collectingproducts of combustion, said collector means being open at the topthereof, a hollow heat exchange unit having a 1ower open endcommunicating with said combustion means and an upper fiue outlet incommunication with and disposed subjacent said collector means adaptedto duct the products of combustion upwardly and to radiate heatgenerated by said fuel combustion means into the space surrounding saidheater, said heat exchange unit comprising a pair of sheet metal panelspositioned back-to-back and having a vertical flat partitiontherebetween, each of said panels being formed with substantiallyV-shaped corrugations, thereby defining in cooperation with saidpartition parallel vertical gas passages, each of said corrugationshaving a ridge formed with inwardly depressed segments extending intosaid gas passage and being in staggered relation with the correspondinginwardly depressed segments of the oppositely disposed panel, therebycausing said products of combustion to follow a sinuous path upwardly,the angle between adjacent walls of said V- shaped corrugations beinggreater than 90, each of said gas passages being open at the topthereof, and means for reflecting said radiant heat downwardly, saidmeans comprising a plurality of spaced parallel horizontally disposedreflector vanes circumscribing said heat exchange unit in spacedrelation therefrom.

11. A radiant-type heater comprising fuel combustion means, collectormeans positioned superadjacent said combustion means for collectingproducts of combustion, said collector means being open at the topthereof, a hollow heat exchange unit having a lower open endcommunicating with said combustion means and an upper flue outlet incommunication with and disposed subjacent said collector means adaptedto duct the products of combustion upwardly and to radiate heatgenerated by said fuel combustion means into the space surrounding saidheater, said heat exchange unit comprising a pair of sheet metal panelspositioned back-to-back and having a vertical flat partitiontherebetween, each of said panels being formed with substantiallyv-shaped corrugations, thereby defining in cooperation with saidpartition parallel vertical triangular-shaped gas passages, each of saidcorrugations having a ridge formed with inwardly depressed segmentsextending into said gas passage and being in staggered relation with thecorresponding inwardly depressed segments of the oppositely disposedpanel, thereby causing said products of combustion to follow a sinuouspath upwardly, each of said gas passages being open at the top thereof.

12. A radiant-type heater comprising fuel combustion means, collectormeans positioned superadjacent said combustion means for collectingproducts of combustion, said collector means being open at the topthereof, a hollow heat exchange unit having a lower open endcommunicating with said combustion means and an upper flue outlet incommunication with and disposed subjacent said collector means adapted13 to duct the products of combustion upwardly and to radiate heatgenerated by said fuel combustion means into the space surrounding saidheater, said heat exchange unit comprising a pair of sheet metal panelspositioned back-toback and having a vertical flat partitiontherebetween, each of said panels being formed with substantiallyV-shaped corrugations, thereby defining in cooperation with saidpartition parallel vertical triangular-shaped gas passages, each of saidcorrugations having a ridge formed with inwardly depressed segmentsextending into said gas passage and being in staggered relation with thecorresponding inwardly depressed segments of the oppositely disposedpanel, thereby causing said products of combustion to follow a sinuouspath upwardly, each of said gas passages being open at the top thereof,and means for reflecting said radiant heat downwardly, said meanscomprising a plurality of spaced parallel horizontally disposedreflector vanes circumscribing said heat exchange unit in spacedrelation therefrom.

13. In a heater adapted to be suspended from a room ceiling, thecombination of fuel combustion means, a generally flat, hollow heatexchange unit superjacent and communicating with said combustion meansto pass products of combustion upwardly therethrough, a plurality ofvertically disposed first straps secured to and disposed adjacent theflat sides of said unit, a plurality of reflector vanes verticallyspaced around said unit, the inner edges of said vanes being disposedhorizontally and secured to said first straps, and a plurality ofvertically disposed second straps secured to said vanes at the outeredges thereof, each vane slanting downward and outward so that the outeredge thereof lies in a lower plane than the inner edge, the undersurfaces of said vanes being finished so as to be predominantlyreflective, the upper surfaces of said vanes being darkened so as to bepredominantly absorptive.

14. An overhead gas burning radiant type heater comprising: asubstantially flat, hollow heat exchange element formed with a pluralityof vertical, partially obstructed passages for hot gases, the outersurfaces of said element being adapted to radiate heat in a generallyhorizontal outward direction, means forming a combustion chambersubjacent said heat exchange element and in communication with the lowerportion thereof, burner means in said chamber whereby products ofcombustion from said burner means will travel upwardly into saidelement, gas collection means superjacent said heat exchange element andin communication with the upper portion thereof, a vent connected tosaid gas collection means to convey away the products of combustion, aplurality of longitudinally horizontal reflectorvanes vertically spacedon both sides of said heat exchange element with the inner edges of saidvanes parallel and adjacent to said heat exchange element, said vanesbeing inclined downwardly and outwardly whereby heat radiated from saidheat exchange element will be reflected downwardly and outwardly, andmeans adapted to suspend said heat exchange element, combustion chambermeans, burner means, gas collection means, and vanes, as a unitarystructure of assembly, from a ceiling.

WILLIAM G. CARTTER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 683,618 Noteman Oct. 1, 19011,198,149 Pioch Sept. 12, 1916 1,726,711 Murray Sept. 3, 1929 1,775,173Phelps et a1 Sept. 9, 1930 1,942,559 Lithman Jan. 9, 1934 1,991,788Cartter Feb. 19, 1935 2,262,158 Beam Nov. 11, 1941 2,439,038 CartterApr. 6, 1948 2,516,285 Winkler et al July 25, 1950 FOREIGN PATENTSNumber Country Date 508,666 France July 30, 1920 429,897 Great BritainJune 7, 1935

